Added http redirect to index.html

[elbcoast]

The Handler has been extended, so that requests that don't have a filename in the path get redirected to the swagger index.html.

Additionally, the regexp for the filename validation has been cleaned up and the filename whitelist has been removed. The implementation now relies on the webdav Handler to create a 404 response if a file can't be found.

[codecov-io]

Codecov Report

Merging #20 into master will decrease coverage by 1.57%.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master   #20      +/-   ##
=======================================
- Coverage   81.57%   80%   -1.58%     
=======================================
  Files           1     1              
  Lines          38    35       -3     
=======================================
- Hits           31    28       -3     
  Misses          5     5              
  Partials        2     2

Impacted Files	Coverage Δ
swagger.go	80% <100%> (-1.58%)	⬇️

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[easonlin404]

LGTM

[easonlin404]

@elbcoast Thanks for your contributions. 💯

[rafbel]

So I am still having this issue. If the path is "/swagger/" it will redirect to "/swagger/index.html", but it won't redirect from "/swagger" to "/swagger/index.html".